Question: $ B = \left[\begin{array}{rrr}2 & 1 & 2 \\ 1 & 2 & 2 \\ 2 & 0 & 0\end{array}\right]$ What is $ B^{-1}$ ?
$ = \left[\begin{array}{rrr}0 & 0 & \frac{1}{2} \\ -1 & 1 & \frac{1}{2} \\ 1 & -\frac{1}{2} & -\frac{3}{4}\end{array}\right]$